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smb: client: handle unlink(2) of files open by different clients

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In order to identify whether a certain file is open by a different
client, start the unlink process by sending a compound request of
CREATE(DELETE_ON_CLOSE) + CLOSE with only FILE_SHARE_DELETE bit set in
smb2_create_req::ShareAccess.  If the file is currently open, then the
server will fail the request with STATUS_SHARING_VIOLATION, in which
case we'll map it to -EBUSY, so __cifs_unlink() will fall back to
silly-rename the file.

This fixes the following case where open(O_CREAT) fails with
-ENOENT (STATUS_DELETE_PENDING) due to file still open by a different
client.

* Before patch

$ mount.cifs //srv/share /mnt/1 -o ...,nosharesock
$ mount.cifs //srv/share /mnt/2 -o ...,nosharesock
$ cd /mnt/1
$ touch foo
$ exec 3<>foo
$ cd /mnt/2
$ rm foo
$ touch foo
touch: cannot touch 'foo': No such file or directory
$ exec 3>&-

* After patch

$ mount.cifs //srv/share /mnt/1 -o ...,nosharesock
$ mount.cifs //srv/share /mnt/2 -o ...,nosharesock
$ cd /mnt/1
$ touch foo
$ exec 3<>foo
$ cd /mnt/2
$ rm foo
$ touch foo
$ exec 3>&-

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: Frank Sorenson <sorenson@redhat.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2025-09-19 14:13:15 -03:00 • committed by Steve French
parent 07e27ad163
commit 1cf9f2a6a5
1 changed files with 89 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

101
fs/smb/client/smb2inode.c
View file

@ -1175,23 +1175,92 @@ int
smb2_unlink(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
struct cifs_sb_info *cifs_sb, struct dentry *dentry)
{
struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
__le16 *utf16_path __free(kfree) = NULL;
int retries = 0, cur_sleep = 1;
struct TCP_Server_Info *server;
struct cifs_open_parms oparms;
struct smb2_create_req *creq;
struct inode *inode = NULL;
struct smb_rqst rqst[2];
struct kvec rsp_iov[2];
struct kvec close_iov;
int resp_buftype[2];
struct cifs_fid fid;
int flags = 0;
__u8 oplock;
int rc;
if (dentry)
inode = d_inode(dentry);
utf16_path = cifs_convert_path_to_utf16(name, cifs_sb);
if (!utf16_path)
return -ENOMEM;
oparms = CIFS_OPARMS(cifs_sb, tcon, name, DELETE,
FILE_OPEN, OPEN_REPARSE_POINT, ACL_NO_MODE);
rc = smb2_compound_op(xid, tcon, cifs_sb, name, &oparms,
NULL, &(int){SMB2_OP_UNLINK},
1, NULL, NULL, NULL, dentry);
if (rc == -EINVAL) {
cifs_dbg(FYI, "invalid lease key, resending request without lease");
rc = smb2_compound_op(xid, tcon, cifs_sb, name, &oparms,
NULL, &(int){SMB2_OP_UNLINK},
1, NULL, NULL, NULL, NULL);
if (smb3_encryption_required(tcon))
flags |= CIFS_TRANSFORM_REQ;
again:
oplock = SMB2_OPLOCK_LEVEL_NONE;
server = cifs_pick_channel(tcon->ses);
memset(rqst, 0, sizeof(rqst));
memset(resp_buftype, 0, sizeof(resp_buftype));
memset(rsp_iov, 0, sizeof(rsp_iov));
rqst[0].rq_iov = open_iov;
rqst[0].rq_nvec = ARRAY_SIZE(open_iov);
oparms = CIFS_OPARMS(cifs_sb, tcon, name, DELETE | FILE_READ_ATTRIBUTES,
FILE_OPEN, CREATE_DELETE_ON_CLOSE |
OPEN_REPARSE_POINT, ACL_NO_MODE);
oparms.fid = &fid;
if (dentry) {
inode = d_inode(dentry);
if (CIFS_I(inode)->lease_granted && server->ops->get_lease_key) {
oplock = SMB2_OPLOCK_LEVEL_LEASE;
server->ops->get_lease_key(inode, &fid);
}
}
rc = SMB2_open_init(tcon, server,
&rqst[0], &oplock, &oparms, utf16_path);
if (rc)
goto err_free;
smb2_set_next_command(tcon, &rqst[0]);
creq = rqst[0].rq_iov[0].iov_base;
creq->ShareAccess = FILE_SHARE_DELETE_LE;
rqst[1].rq_iov = &close_iov;
rqst[1].rq_nvec = 1;
rc = SMB2_close_init(tcon, server, &rqst[1],
COMPOUND_FID, COMPOUND_FID, false);
smb2_set_related(&rqst[1]);
if (rc)
goto err_free;
if (retries) {
for (int i = 0; i < ARRAY_SIZE(rqst); i++)
smb2_set_replay(server, &rqst[i]);
}
rc = compound_send_recv(xid, tcon->ses, server, flags,
ARRAY_SIZE(rqst), rqst,
resp_buftype, rsp_iov);
SMB2_open_free(&rqst[0]);
SMB2_close_free(&rqst[1]);
free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
if (is_replayable_error(rc) &&
smb2_should_replay(tcon, &retries, &cur_sleep))
goto again;
/* Retry compound request without lease */
if (rc == -EINVAL && dentry) {
dentry = NULL;
retries = 0;
cur_sleep = 1;
goto again;
}
/*
* If dentry (hence, inode) is NULL, lease break is going to
@ -1199,6 +1268,14 @@ smb2_unlink(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
*/
if (!rc && inode)
cifs_mark_open_handles_for_deleted_file(inode, name);
return rc;
err_free:
SMB2_open_free(&rqst[0]);
SMB2_close_free(&rqst[1]);
free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
return rc;
}